Dr Chris O'Meara

Delighted to be awarded a British Academy Global Innovation Fellowship at the Carnegie Endowment for International Peace! Starting in September, I’ll be based in Washington DC, researching security & defence, with a focus on space governance and the militarisation of outer space.

What limits does international law place on using force in self-defence in the cyber context? See my new ECIL Working Paper on how the customary international law requirements of necessity and proportionality apply to cyber operations: tinyurl.com/mrxhmszr

Missiles and Messages: Characterizing the Use of Force between Iran and Israel [Masoud Zamani is a lecturer in International Law and International Relations at the University of British Columbia, Canada.  Amir Abbas Kiani is a collaborating researcher in Intern…

Missiles and Messages: Characterizing the Use of Force between Iran and Israel

opiniojuris.org/2025/07/25/m...

Are we witnessing the death of international law? The long read: A growing number of scholars and lawyers are losing faith in the current system. Others say the law is not to blame, but the states that are supposed to uphold it

“what we are witnessing today is not the failure of international law but rather the failure of international politics”. Discuss

www.theguardian.com/law/2025/jun...

The Illegal Israeli-American Use of Force Against Iran: A Follow-Up Yesterday, the United States joined Israel in its use of force against Iran by conducting a precision bombing operation targeting Iranian nuclear sites. Like Israel’s use of force before it, this use ...

Spot on again from Marko. Note to the UK gov: ‘Third states have a legal obligation to refrain from providing aid and assistance to unlawful uses of force.’

www.ejiltalk.org/the-illegal-...

Indefensible: Israel’s Unlawful Attack on Iran Legal scholars assess how the UN Charter and international law applies to Israel's strike on Iran's nuclear and other facilities.

www.justsecurity.org/115010/israe...

Is Israel’s Use of Force Against Iran Justified by Self-Defence? This morning, Israel launched a major military operation against Iran targeting its nuclear programme, including facilities, individual scientists and military leadership. In this post, I will provide...

Is Israel’s Use of Force Against Iran Justified by Self-Defence? www.ejiltalk.org/is-israels-u... I broadly agree with Marko’s analysis and conclusion of unlawfulness. For more on ‘imminence’ and its relationship (conflation?) with necessity, my thoughts are here: doi.org/10.1080/2053...

❗️Come and join the Legal Division of the @ICRC!

✴️ Turn your vision for a better world, your belief in justice and humanity, in the protective power of the law, into #IHL advocacy.

careers.icrc.org/job/Geneva-%...

A matter of time: the role of timing in regulating military weapons What challenges and opportunities are presented when efforts are made to regulate or prohibit morally problematic battlefield weapons or practices ex ante—

🚨 Thrilled to announce that my latest article, with the amazing Sarah Percy, has been published with International Affairs. Drawing on historical cases, we explore the role of timing in the legal regulation of battlefield weapons and practices.
academic.oup.com/ia/advance-a...

Balancing State Security and Peace and Security in Outer Space Understanding jus ad bellum necessity and proportionality is crucial to addressing concerns regarding the weaponization of outer space.

With #UN Working Group on Prevention of an Arms Race in #OuterSpace underway, @chrisomeara.bsky.social analyzes how jus ad bellum principles relate to use of space weapons in self-defense.

www.justsecurity.org/110248/secur...

Balancing State Security and Peace and Security in Outer Space Understanding jus ad bellum necessity and proportionality is crucial to addressing concerns regarding the weaponization of outer space.

As the UN General Assembly’s new OEWG on the Prevention of an Arms Race in Outer Space holds its first substantive session this week, what role can existing international law play? Here's my take: www.justsecurity.org/110248/secur...

ANZSIL registration is now open! @djag2.bsky.social and I are co-chairing the organising committee this year and we think it's going to be an awesome conference. The Conference theme is 'International Law: Silence, Forgetting and Remembrance'.
anzsil.org/event-6142429

Ten Britons accused of committing war crimes while fighting for Israel in Gaza Exclusive: Met to be handed dossier of evidence alleging crimes including killings of civilians and aid workers

Important.

Also, potentially interesting role of open source investigations

www.theguardian.com/law/2025/apr...

Is the imposition of tariffs a form of economic coercion and an unlawful intervention in the domestic affairs of other states? Check out my recent book, pp. 170-186: shorturl.at/BvMsw #trump #tariffs #nonintervention

How does the law limit self-defence in outer space? In my latest article for the Leiden Journal of International Law, I examine how international law on the use of force regulates the use of anti-satellite (#ASAT) weapons.

Link: doi.org/10.1017/S092...

War Above the Battlefield: Continued

Join us for part II of our online panel discussion exploring the resilience of Ukraine’s air defence & the challenges of Russia’s use of counterspace capabilities.

📅 4 April
⏲️ 15:30 – 16:30
📌 Zoom

Register 👇
www.kcl.ac.uk/events/war-a...

Former 🇺🇸 ambassador to Russia 👇🏽

AI is transforming the security landscape, influencing decision-making, risk assessment & strategic stability 🧭

In the #MiddleEast, these dynamics play a crucial role in discussions on establishing a Weapons of Mass Destruction-Free Zone 📜

Read more 📙 unidir.org/ZoneAI

The exercise of self-defence in outer space | Dr Rishi Gulati with guest Dr Chris O'Meara Podcast Episode · UEA Law School Podcast Series · 28/02/2025 · 49m

Space law fan? If so, check out the discussion with Dr Rishi Gulati of my paper on the right of self-defence in outer space (forthcoming, Leiden Journal of International Law):

podcasts.apple.com/gb/podcast/t...

soundcloud.com/law-office-8...

⏰TODAY⏰

Join us today for an online panel discussion exploring the resilience of Ukraine’s air defence & the challenges of Russia’s use of counterspace capabilities.

📅 28 Feb
⏲️15:00 GMT

Register now 👇
kcl.ac.uk/events/war-a...

Interested in military operations in outer space and space law? Sign up here if so! www.eventbrite.com/e/uk-launch-...

Join Kubo Mačák @exeter.ac.uk @uniofexeterhass.bsky.social
UK launch Woomera Manual: International Law of Military Space Activities and Operations🚀

📅 Wednesday 12 March
📍 @rusi.bsky.social London
⏰16:00 doors 16:30–19:00 (panel & reception)
🎟 Register
www.eventbrite.co.uk/e/1254442604...

IHL in Focus Annual Report: Assessing Compliance Across 22 Conflicts - The Geneva Academy of International Humanitarian Law and Human Rights The IHL in Focus: Annual Report, which documents and analyses compliance with International Humanitarian Law (IHL) in some of the world’s most pressing conflicts, is now available.

📖 Launched today – IHL in Focus: Annual Report.

Documenting and analysing compliance with IHL in some of the world’s most pressing conflicts, it sheds light on the well-documented crises dominating global headlines.

👉 Read more and download the report: www.geneva-academy.ch/news/detail/...

Annual Grotius Lecture 2025: The Advisory Opinion of ITLOS on Climate Change: A Landmark Decision Thursday, 27 March 2025, British Institute of International and Comparative Law, Charles Clore House, 17 Russell Square, London WC1B 5JP

📢 We are pleased to invite you to the Annual Grotius Lecture 2025, where Judge Tomas Heidar will discuss the Advisory Opinion of #ITLOS on #ClimateChange: A Landmark Decision.

📅 27 March 2025 | 🕔 17:30-18:30 | 📍 BIICL, London

Find out more and register for free 👇

Most Ukrainian cities have not been destroyed.

Ukrainian law prohibits holding elections in wartime (unlike the US Constitution, which requires it).

isw.pub/UkraineFacts...

Trump’s Gaza Plan is Absurd and an Affront to International Law Beyond complicating the chances of a permanent ceasefire in Gaza, the idea undermines core principles of the international legal order and threatens U.S. interests.

U.S. President Donald Trump has repeatedly called for a plan to resettle the entire Palestinian population of Gaza to Egypt and Jordan.

Professor @eliavl.bsky.social writes that the idea undermines core principles of the international legal order and threatens U.S. interests.

There’s a Term for What Trump and Musk Are Doing How regime change happens in America

Did Musk fire hundreds of Federal Aviation Administration employees to increase "efficiency"? I don't think so. There is a better explanation:

www.theatlantic.com/ideas/archiv...

As the US walks away, Europe needs to step up for Ukraine. But does it have the will? Russia is relying on strength of numbers, and Putin may not honour a peace deal

www.theguardian.com/world/2025/f...

YouTube video by Ministry of Defence All about Tyche: UK Space Command’s first satellite

Watch this YouTube video to learn about Tyche, the UK’s first defence satellite 👉 youtu.be/1hpTlC3DWYQ

Read more about Oberon 👉 www.gov.uk/government/n...